That’s the cool thing about data: there are many ways to visualize, and this series was meant – next to some groundwork on how to get the data – as inspiration into some forms of visualization.
Hope you had fun reading it!

the category slug is the unique value for a category that WordPress uses to form category urls. It is auto-generated from the Category, but you can also edit it. I don’t, as it is not in the combobox HTML, so I derive it from the Category. Note there are also posting slugs used in the permalink of each post.

The bulk of the above code is in the splitValue method (that could have used RegEx, but I try to avoid RegEx when I can do without it).
Note that the HtmlPath propererty uses the parent property. Without it, the HtmlPath code would have been very complex. The value of the parent properties for all optionType instances is generated in the selectType.FixParents method below since the selectType instance contains all the optionType instances in its’ option property.